1. Field of the Invention
The present invention relates to a high power semiconductor laser device and, more particularly, to a method of manufacturing a semiconductor laser device which includes an efficiently improved metal bonding process of a high power semiconductor laser array.
2. Description of the Related Art
Recently, high power semiconductor laser devices are extensively used in various applications such as industrial and medical fields including optical communication, optical recording devices, welding and dicing, and are also beginning to be applied to visible ray lasers for display, and thus expected to have further expanded applications.
In general, it is impossible to manufacture a laser apparatus of more than tens of watts with a single semiconductor laser device. Thus, in order to obtain a high power laser, an array type semiconductor laser device is used with several laser diodes arranged in the form of a bar.
In order to obtain light output of tens of watts, high current exceeding tens of amperes is applied, causing a considerable amount of heat in the laser array itself. If the heat is not appropriately discharged, the light output is degraded and the lifetime of the chip is shortened.
To overcome such problematic conditions, the array type laser device in general is provided in a package in which a laser array (or a laser bar) 10 is mounted on a base 21 of high heat conductivity using a metal bonding layer 29 such as solder.
In order to manufacture the conventional array type semiconductor laser device 20 into a package as shown in FIG. 1b, the bar-shaped laser array 10 is mounted on an upper surface of the base 21 with the metal bonding layer 29 deposited thereon as shown in FIG. 1a. 
The laser array 10 includes a semiconductor laser stack structure 10′ formed on a conductive substrate 11 and first and second electrodes 17 and 18 formed on upper and lower surfaces thereof. The laser array 10 requires a heat-treating process after the first and second electrodes 17 and 18 are formed, and thus has the metal bonding layer 29, which tends to be relatively easily melted at high temperature, formed on an upper surface of the base 21.
However, the base is usually manufactured for each unit package, and thus requires an individual deposition process of the metal bonding layer, which adversely affects the efficiency of the manufacturing process and a yield.
Further, as shown in FIG. 1b, when the laser array is heat-pressed on an upper surface of the base with the metal bonding layer provided thereon, the metal bonding material being melted for bonding may spread along the surface of the semiconductor laser array as denoted by the reference sign S, potentially causing short circuit of the laser.